Adds two experimental tags

entropy_stats: to generate stats of various symbols encoded
masked_tx: new experiemnt for coding a smaller transform in a
           prediction block

Change-Id: I48baf0f1c37245c43031a9eda879ef49eee5e76b
diff --git a/configure b/configure
index 5220b2c..4438841 100755
--- a/configure
+++ b/configure
@@ -298,6 +298,8 @@
     rd_debug
     reference_buffer
     coef_interleave
+    entropy_stats
+    masked_tx
 "
 CONFIG_LIST="
     dependency_tracking